Low-energy Bluetooth is really starting to take-off in a big way, with seemingly every other product on the main crowdsourced-funding sites using it. One product that actually exists, though, is the Elgato Smart Key – which appears good value at just $40.

If you can’t remember where you last saw your keys, the Elgato Smart Key iPhone app will tell you the GPS location of where the two devices were last in contact. Through the app you’ll also be able to make the Smart Key play a sound to help you find your keys when they are down the back of the sofa. Not only that, but attach them to your keys and your iPhone will alert you when you walk off and leave them somewhere. Leave one in the glove compartment of your car, and the app will show you were you parked a if you need reminding …

Bluetooth LE has a very short range, often as low as 30 feet or so in smaller devices. It’s thus great for alerting you when you’re about to walk off leaving your keys or bag behind, not so good at finding your car in a car-park. What the Smart Key app does is to mark the location of the key when your phone goes out of range, so you can use GPS to locate it from further away.

Sources say that Apple is testing a tool for its Maps app that, with the M7 chip, could analyze when your car is parked. When you park your car, the iPhone will register the car’s location. Now when you return to the parking lot, your iPhone will be able to help you assist with finding your car since it knows the vehicle’s location.

That approach would not, of course, help you track portable items like keys and bags, but should work well to find your car or bicycle.

The Smart Key is IP65 certified, meaning it’s 100 percent dust-proof and can resist heavy water spray, but not total immersion. Elgato claims the user-replaceable battery will last for six months.

The Elgato Smart Key is available from Amazon for $39.95 with free shipping. Stock appears to be limited at present.